The present invention relates to higher picture quality televisions such as a high definition television (HDTV), and more particularly to a motion vector detecting method of a video signal capable of effectively detecting an interframe motion vector in order to process a pseudo-moving image.
Typically, a well known motion vector is to express the motion direction and the motion amount of a current frame in comparison with a previous frame to a vector quantity of a pixel unit in the image of two consecutive frames. According to a variation factor between two frames, the motion vector is classified into an intraframe motion vector for an object within the frame and an interframe motion vector caused by the panning of a camera.
In MUSE system developed by N.H.K. of Japan, a video signal is divided into a moving region, a stationary region and a pseudo-moving region according to a reproducing method at a receiver side. The pseudo-moving region means that an entire screen moves by the panning of the camera, for example. When the image of a previous frame shown in FIG. 1A moves fight and upward at a current frame as shown in FIG. 1B, if the image is processes to the moving region, the softing of the image occurs at the receiver side as indicated in FIG. 1C. Therefore, in the case that the entire screen instead of an object within the screen moves, the MUSE system processes the image to the pseudo-moving region. In this case, the motion between frames, i.e. the interframe motion vector, is detected and the detected motion vector is sent to the receiver side. If the receiver side reads out previous frame information within a frame memory by shifting an address as much as the motion of the image, the image can be processed to the pseudo-moving image as shown in FIG. 1D.
As methods for obtaining the interframe motion vector, an absolute error and a mean square error for calculating a minimum motion amount between consecutive images, and a cross correlation for obtaining a maximum motion amount have been used. However, these methods have slow operation processing speed and complicate hardware.